1. Field of the Invention
The present invention relates to a multi-type air conditioning apparatus in which one or more indoor units are connected to an outdoor unit.
2. Description of the Related Art
There is known a multi-type air conditioning apparatus in which two or more indoor units are connected to an outdoor unit. Indoor units include units called personal air conditioninq units, which are used to air-condition indoor spaces individually. The personal air conditioninq units are mounted on, for example, a number of desks placed on the indoor floor.
In installing an air conditioning apparatus equipped with one or more personal air conditioning units in an office in a building, it is a practical method to install a refrigerant pipe and a drain pipe in the underfloor space, the so-called free access floor.
However, the free access floor is prepared to accommodate electrical wiring for computers and business equipment, and its depth is limited to about ten centimeters at most. The depth limit is intended to circumvent bad effects, which would be produced by making the depth of the free access floor too great, such as inconvenient entrance and exit resulting from increased difference in level between a room and a hall, and an oppressive sensation resulting from low ceiling.
Even if a drain pipe is laid down in such a free access floor, it is almost impossible to tilt it. For this reason, dust is liable to accumulate in the drain pipe, and thus the drain pipe can be blocked up.
One way to solve such a problem would be forming an opening in a concrete slab under the free access floor and conducting the drain pipe downstairs through the opening. However, this way would require a new opening to be formed in the concrete slab each time the arrangement of desks on the floor is changed, and an old opening to be stopped up. Therefore, this construction would be very troublesome and time-consuming.
In Japanese Unexamined Patent Publication No. 2(HEISEI)-254237 there is disclosed an air conditioning apparatus in which drainage produced by a cooler is caught by a drainage pan, the drain in the drain pan is conducted into a tank, and the drainage in the tank is evaporated and then exhausted outdoors. A problem with this air conditioning apparatus is that the entire apparatus has to become large because a tank having a built-in drain evaporating means is provided for each of a plurality of coolers.
Moreover, in Japanese Unexamined Utility Model Publication No. 2(HEISEI)- 93620 there is disclosed an air conditioning apparatus in which drain produced by an air conditioning unit mounted on a desk is evaporated by heat of high-temperature refrigerant passing through a refrigerant pipe and then discharged outdoors. In the case of this air conditioning apparatus as well, means for evaporating drainage is needed for each of air conditioning units mounted on desks. Thus, the entire apparatus inevitably becomes large.
Furthermore, in Japanese Unexamined Utility Model Publication No. 2(HEISEI)- 93621 there is disclosed an air conditioning apparatus in which drainage produced by an air conditioning unit mounted on a desk is stored in a tank, and the drainage in the tank is converted into oxygen and hydrogen by means of electrolysis, the oxygen being sent back into the indoor space and the hydrogen being discharged outdoors. In the case of this air conditioning apparatus as well, the entire apparatus becomes large because electrolysis means is needed for each of air conditioning units mounted on desks.